<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Mysql.php 23986 2011-05-03 20:10:42Z ralph $
 */

/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';

/**
 * Class for connecting to MySQL databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Mysql extends Zend_Db_Adapter_Pdo_Abstract {
	
	/**
	 * PDO type.
	 *
	 * @var string
	 */
	protected $_pdoType = 'mysql';
	
	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array (Zend_Db::INT_TYPE => Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE, Zend_Db::FLOAT_TYPE => Zend_Db::FLOAT_TYPE, 'INT' => Zend_Db::INT_TYPE, 'INTEGER' => Zend_Db::INT_TYPE, 'MEDIUMINT' => Zend_Db::INT_TYPE, 'SMALLINT' => Zend_Db::INT_TYPE, 'TINYINT' => Zend_Db::INT_TYPE, 'BIGINT' => Zend_Db::BIGINT_TYPE, 'SERIAL' => Zend_Db::BIGINT_TYPE, 'DEC' => Zend_Db::FLOAT_TYPE, 'DECIMAL' => Zend_Db::FLOAT_TYPE, 'DOUBLE' => Zend_Db::FLOAT_TYPE, 'DOUBLE PRECISION' => Zend_Db::FLOAT_TYPE, 'FIXED' => Zend_Db::FLOAT_TYPE, 'FLOAT' => Zend_Db::FLOAT_TYPE );
	
	/**
	 * Override _dsn() and ensure that charset is incorporated in mysql
	 * @see Zend_Db_Adapter_Pdo_Abstract::_dsn()
	 */
	protected function _dsn() {
		$dsn = parent::_dsn ();
		if (isset ( $this->_config ['charset'] )) {
			$dsn .= ';charset=' . $this->_config ['charset'];
		}
		return $dsn;
	}
	
	/**
	 * Creates a PDO object and connects to the database.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _connect() {
		if ($this->_connection) {
			return;
		}
		
		if (! empty ( $this->_config ['charset'] )) {
			$initCommand = "SET NAMES '" . $this->_config ['charset'] . "'";
			$this->_config ['driver_options'] [1002] = $initCommand; // 1002 = PDO::MYSQL_ATTR_INIT_COMMAND
		}
		
		parent::_connect ();
	}
	
	/**
	 * @return string
	 */
	public function getQuoteIdentifierSymbol() {
		return "`";
	}
	
	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables() {
		return $this->fetchCol ( 'SHOW TABLES' );
	}
	
	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null) {
		// @todo  use INFORMATION_SCHEMA someday when MySQL's
		// implementation has reasonably good performance and
		// the version with this improvement is in wide use.
		

		if ($schemaName) {
			$sql = 'DESCRIBE ' . $this->quoteIdentifier ( "$schemaName.$tableName", true );
		} else {
			$sql = 'DESCRIBE ' . $this->quoteIdentifier ( $tableName, true );
		}
		$stmt = $this->query ( $sql );
		
		// Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
		$result = $stmt->fetchAll ( Zend_Db::FETCH_NUM );
		
		$field = 0;
		$type = 1;
		$null = 2;
		$key = 3;
		$default = 4;
		$extra = 5;
		
		$desc = array ();
		$i = 1;
		$p = 1;
		foreach ( $result as $row ) {
			list ( $length, $scale, $precision, $unsigned, $primary, $primaryPosition, $identity ) = array (null, null, null, null, false, null, false );
			if (preg_match ( '/unsigned/', $row [$type] )) {
				$unsigned = true;
			}
			if (preg_match ( '/^((?:var)?char)\((\d+)\)/', $row [$type], $matches )) {
				$row [$type] = $matches [1];
				$length = $matches [2];
			} else if (preg_match ( '/^decimal\((\d+),(\d+)\)/', $row [$type], $matches )) {
				$row [$type] = 'decimal';
				$precision = $matches [1];
				$scale = $matches [2];
			} else if (preg_match ( '/^float\((\d+),(\d+)\)/', $row [$type], $matches )) {
				$row [$type] = 'float';
				$precision = $matches [1];
				$scale = $matches [2];
			} else if (preg_match ( '/^((?:big|medium|small|tiny)?int)\((\d+)\)/', $row [$type], $matches )) {
				$row [$type] = $matches [1];
			
		// The optional argument of a MySQL int type is not precision
			// or length; it is only a hint for display width.
			}
			if (strtoupper ( $row [$key] ) == 'PRI') {
				$primary = true;
				$primaryPosition = $p;
				if ($row [$extra] == 'auto_increment') {
					$identity = true;
				} else {
					$identity = false;
				}
				++ $p;
			}
			$desc [$this->foldCase ( $row [$field] )] = array ('SCHEMA_NAME' => null, // @todo
'TABLE_NAME' => $this->foldCase ( $tableName ), 'COLUMN_NAME' => $this->foldCase ( $row [$field] ), 'COLUMN_POSITION' => $i, 'DATA_TYPE' => $row [$type], 'DEFAULT' => $row [$default], 'NULLABLE' => ( bool ) ($row [$null] == 'YES'), 'LENGTH' => $length, 'SCALE' => $scale, 'PRECISION' => $precision, 'UNSIGNED' => $unsigned, 'PRIMARY' => $primary, 'PRIMARY_POSITION' => $primaryPosition, 'IDENTITY' => $identity );
			++ $i;
		}
		return $desc;
	}
	
	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param  string $sql
	 * @param  integer $count
	 * @param  integer $offset OPTIONAL
	 * @throws Zend_Db_Adapter_Exception
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0) {
		$count = intval ( $count );
		if ($count <= 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception ( "LIMIT argument count=$count is not valid" );
		}
		
		$offset = intval ( $offset );
		if ($offset < 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception ( "LIMIT argument offset=$offset is not valid" );
		}
		
		$sql .= " LIMIT $count";
		if ($offset > 0) {
			$sql .= " OFFSET $offset";
		}
		
		return $sql;
	}

}
